Isn't 550400 G-summat-or-other?
And 002200 A-summat-or-other?

I use those as the 4 and 5 chords for the key of D.
Not saying I'm right, just wondering.

I never bother about naming chords in DADGAD, or trying to use the 'proper' shapes. I just stick my fingers on a few frets and jiffle 'em around until it sounds 'right'. Seems to be a beautiful thing about this tuning that its modal nature and the use of dissonants means that it's very forgiving and allows the player a lot of wriggle-room in finding 'chords' that work.

Seems that way to me, anyway. Nobody's complained! :-) :-)